AFB1

Aflatoxin B1 (AFB1) is a toxic secondary metabolite produced mainly by Aspergillus flavus and Aspergillus parasiticus. It is one of the most potent naturally occurring hepatotoxic and carcinogenic compounds known.

AFB1 occurs in agricultural commodities such as maize, peanuts, tree nuts, cottonseed, and spices, particularly under warm, humid conditions and during storage when moisture is high. Contamination can begin in the field and continue during storage, handling, or processing.

Toxicology and mechanism: AFB1 is classified by IARC as a Group 1 carcinogen. In the body, it is bioactivated by hepatic cytochrome P450 enzymes to the reactive AFB1-8,9-epoxide, which forms adducts with DNA, especially at guanine residues, leading to mutations such as in the TP53 gene. Chronic exposure is linked to hepatocellular carcinoma; synergistic effects exist with hepatitis B virus infection.

Clinical effects: chronic exposure can cause liver damage and cancer; acute aflatoxicosis is possible at very high intakes, causing acute liver failure and hemorrhage. Risk factors include age, malnutrition, and concurrent liver disease.

Regulation and safety: Many countries regulate AFB1 limits in foods; levels vary by product and jurisdiction. Detection methods include ELISA, high-performance liquid chromatography with fluorescence detection (HPLC-FLD), and LC-MS/MS. Prevention focuses on good agricultural and storage practices, drying, cleaning, sorting, and post-harvest management to reduce fungal growth and toxin production.